This application claims benefit of Japanese Patent Application No. 2000-193377 filed on Jun. 27, 2000, the contents of which are incorporated by the reference.
The present invention relates to optical fibers used for light transmission paths and, more particularly, to optical connector (coupler) coupling end face state confirmation scope and optical connector coupling end face state confirmation method for confirming the state of the coupling end face of an optical connector optically coupled with an optical fiber.
An optical fiber used for an optical transmission path is optically coupled by an optical connector. The optical connector is accommodated in an optical connector housing, which may have various shapes depending on the shape of the optical connector. Recent optical fibers required for light transmission have core portions which are extremely reduced in diameter from about 10 xcexcm or below.
In an optical connector for optically coupling two optical fibers, the axial alignment of the optical fibers is made such that the core portions thereof are coupled together in an overlap relation to each other for preventing coupling loss. Also, since the core portion is small in diameter, even very small foreign particles present at the end face of the core portion to be optically coupled, enhances the coupling loss. For this reason, in addition to the axial optical fiber alignment, usually the core portion coupling end face of the optical connector is cleaned by inserting a thin cleaning tool such as a cotton bar. In this way, the end face of the core portion should be held free from any foreign matter.
However, in the prior art in which the core portion coupling end face of the optical connector is cleaned with a cotton bar or the like, the following problems are posed. For example, first problem is that foreign matter such as yarn pieces may be generated by the cleaning tools such as the cotton bar itself. Unless the generation of the foreign matter such as yarn pieces is found out, the foreign matter remains and is not perfectly removed, thus posing again the problem of the coupling loss increase. A second problem is that scars and scratches on the core portion due to unsatisfactory handling of the optical connector poses the problems of coupling loss increase and so forth. Unless such scars and scratches are found out, they remain on the coupling end face of the optical connector, and are not perfectly removed. Like the first problem, again this poses the problem of coupling loss increase. A third problem is that when such problem as coupling loss increase arises on the coupling end face of the optical connector in the optical transmission path, it is difficult to pin-point an optical connector as the cause of the problem among a plurality of optical connectors.
In other words, the common cause of the above problems resides in that it is impossible to confirm the state of the coupling end face of the optical connector.
The present invention was made in view of the above problems, and it has an object of providing an optical connector coupling end face state confirmation scope and an optical connector coupling end face state confirmation method, which permit ready confirmation of the state of the coupling end face of the optical connector and ready confirmation of foreign matter and scars and scratches on the core portion.
According to an aspect of the present invention, there is provided an optical connector coupling end face state confirmation scope comprising: a probe for illuminating and enlargingly imaging the coupling end face of the optical connector; an attachment for disposing the coupling end face of the optical connector on the optical axis of the probe and causing the coupling end face of the optical connector to be focused in a position inside the probe; and a monitor unit for monitoring the image of the state of the coupling end face of the optical connector obtained by enlarging imaging by the probe. With this means, it is possible to confirm the state of the coupling end face of the optical connector, readily confirm foreign matter and scars, etc. on the optical fiber core portion and prevent coupling loss increase.
The attachment has a shape corresponding to the shape of an optical connector housing accommodating the optical connector. With this means, it is possible to cope with various optical connectors and optical connector housings by changing the attachment.
The attachment has a guide hole with the probe inserted therein, the guide hole being formed such as to fit the outer diameter of the probe. With this means, it is possible to dispose the coupling end face of the optical connector on the optical axis of the probe.
The distance between the coupling end face of the optical connector disposed in the attachment and an objective lens disposed inside the probe is set to a predetermined value such as to have the coupling end face of the optical connector be fixed in a position inside the probe. With this means, the coupling end face of the optical connector can be optically enlargingly imaged by the objective lens.
The probe includes a light-emitting diode for illuminating the coupling end face of the optical connector and a half mirror for reflecting light emitted from the light-emitting diode at an angle of 90 degrees toward the coupling end face of the optical connector and transmitting light reflected by the coupling end face of the optical connector to have an image of the coupling end face of the optical connector be focused in a position within the probe. With this means, the coupling end face of the optical connector is illuminated by the light-emitting diode.
A light absorbing sheet is applied to the inner surface of the probe at a position thereof, on which light emitted from the light-emitting diode and transmitted through the half mirror is incident. With this means, it is possible to eliminate adverse effects of an image which is otherwise formed on the inner surface of the probe by light emitted from the light-emitting diode and transmitted through the half mirror on the image of the coupling end face of the optical connector.
The probe includes a holder, to which an imaging element for imaging the coupling end face of the optical connector is secured, a guide for guiding the straight movement of the holder for moving the imaging element along the optical axis of the probe and a slide for giving a drive force to the holder for straight movement of the guide. The focus position may vary slightly depending on the kind of the optical connector and optical connector housing and also by manufacturing fluctuations of the attachment and other components. With the above means, it is possible to accurately adjust the position of the coupling end face of the imaging element to the focus position.
The slider has hook means for transmitting a drive force therethrough to the holder, the hook means being separated from the holder and the guide. With this means, when manually causing the sliding operation of the slide, the stress generated in the slide in a direction perpendicular to the sliding direction is not applied to the holder, and it is possible to obtain stable straight movement of the slide.
The hook means of the slide has a plate-like portion for preventing external scattered light from entering from a guide groove for guiding the straight movement of the slide. With this means, intrusion of external scattered light is prevented, and it is thus possible to prevent deterioration of the light image on the coupling end face of the optical connector.
The coupling end face of the optical connector is the coupling end face of a single-core optical connector or the coupling end face of a multiple-core optical connector. With this means, it is possible to apply the present invention not only to single-core optical connectors but also to multiple-core optical connectors.
According to another aspect of the present invention, there is provided an optical connector coupling end face state confirmation apparatus comprising means for illuminating and enlargingly imaging the coupling end face of the optical connector, and means for monitoring the image obtained by the enlarging imaging of the coupling end face of the optical connector.
According to other aspect of the present invention, there is provided an optical connector coupling end face state confirmation method comprising: a step of illuminating and enlargingly imaging the coupling end face of the optical connector; and a step of monitoring the image obtained by the enlarging imaging of the coupling end face of the optical connector. With this means, like the above-mentioned case, it is possible to confirm the coupling end face of the optical connector, readily confirm foreign matter and scars and scratches of the optical fiber core portion and prevent coupling loss increase.
Other objects and features will be clarified from the following description with reference to attached drawings.